Pulverized-fuel burner.



PULVERIZED-PUEL BURNER.

Specification of Letters Patent.

' Patented Jan. so, act t,

Application filed J u1y'16, 1915. Serial No. 40,174.

To all whom it may concern:

Be it known that T, LARs H. BERGMAN, a subject of the King of Sweden,residing at Philadelphia, county of Philadelphia, and State ofPennsylvania, have invented a new and useful Improvement inPulverized-Fuel Burners, of which the following is a full, clear, andexact description, reference being had to the accompanying drawings,which form a part of this specification.

The invention relates to pulverized fuel burners for furnaces, boilersand kilns wherein air is employed both to atomize and propel the fueland to effect combustion.

The main object of the invention is to so construct the burner as torequire only one source of air supply. This object is effected by aconstruction in which the common supply of air is so divided that partthereof used for combustion is supplied either on the outside or on theinside of the stream of air employed for atomizing and carrying thefuel.

In this patent there is set forth and specifically claimed an embodimentof the invention, wherein air of comparatively low pressure, is used andwherein the combustion air takes a path centrally within the stream offuel atomizing and carrying air. In an application of even dateherewith, Serial No. $0,173, there is set forth and specifically claimeda construction wherein air of comparatively'high pressure is used andwherein the combustion takes a path centrally within the stream of fuelatomizing and carrying air, such application also claiming the subjectmatter common to it and this patent. In another application of even dateherewith, Serial No. 40,172, there is set forth and specifically claimeda construction wherein the combustion air takes a path surrounding thepassage for the fuel and atomizing and carrying air; the last-namedapplication also claiming the subject-matter common to all arrangements.

Tn the drawings, which show a preferred embodiment of the invention,Figure 1 is an elevation, and Fig. 2 a vertical section' through theburner and fuel hopper, and Pig. 3 a section on line 33 of Figa 2.

The main pipe f of the burner has an inlet or hopper I) connected to apipe a, through which the fuel, fed thereinto in proper and uniformamount by any known means, drops by gravity. The rear wall 0 of thehopper,

which presents a convex surface, is inclined downwardly and forwardly todistribute fuel over the cone (Z; the face of this cone (Z being locatedat a Suitable distance to the rear of the vertical front wall of thehopper, forming a fuel delivery mouth 6.

Pipe f is connected with a source of air supply provided with a damper mwhereby the volume of air within the burner may be regulated. Theforward part 9 of pipe f is shown conical, but may be of any othercontracted form, giving the fuel and air leaving the burner a contractedshape, preventing the combustion from taking place too near the burnernozzle. The inner pipe it dividing up the common source of air supply ismade in a separate piece and is preferably shaped conical at each end.The inside face of cone cl extends for some distance toward the rear ofthe burner, affording, in connection with the conical shape of the rearof pipe h, a gradually contracting passage for the atomizing andpropelling air before it reaches the fuel delivered from the hopper,thereby causing the air at the forward end of cone d to buildup aslightly higher pressure, insuring a maximum speed of air through theopening 00. This opening is located at such a distance behind the frontof the coal inlet 6 that a slight suction is created within the hopper,the fuel being partly dropped and partly drawn into the flow of air bythe latters inducingeifect; The burner pipe h is adjustable and held indesired position by means of set screws i so located that they donotobstruct the low of the fuel carried by the atomizing air. Byadjusting the pipe h the area admitting the atomizing air may beincreased or decreased, thus increasing or decreasing the volume ofatomizing air to suit the. consumption on each particular furnace.

From the foregoing description it will be understood that the pulverizedfuel is dropped throughpipe a and hopper b and air of comparative lowpressure from a common source of supply is divided by means of innerpipe it into two streams; one the fuel atomizing and propelling airpassing within the annular space between inner pipe and cone 0?, thisspace being so located in relation to fuel hopper b that the fuel ispartly dropped and partly drawn into the air which conveys the fueltoward the discharge end of cone g, while the other stream-thecombustion airgoes through pipe h, entering the furnace in the center ofthe fuel carried by the atomizing air.

Having now fully described my invention, What I claim and desire toprotect by Letters Patent is:

1. A pulverized fuel burner comprising an outer pipe, an inner pipeinclosing a combustion ai'r passage and affording between it and theouter pipe a passage for fuel and for fuel at'omizing and conveying air,an inlet for air common to both pipes, a fuel hopper communicating Withthe space between said pipes, said pipes being arranged to form a.forwardly contracting annular passage, baclg of said fuel inlet, whosemouth is located to the rear of the front wall of the hopper.

2. A pulverized fuel .burner comprising an outer pipe, a fuel hopper, aninner pipe inclosing a combustion air passage and affording between itand the outer pipe a passage for fuel and for fuel atomizing andconveying air, and an inlet for air common to both pipes, the outer pipehaving a conical portion whose front edge terminates back of the frontwall of the hopper.-

3. A pulverized fuel burner comprising an outer pipe, a fuel hopper, aninner pipe inclosing a combustion air passage and affordingbetween itand the outer pipe a pas sage for fuel and for fuel atomizing andconveying air, and an inlet for air common to both pipes, the outer pipehaving a conof air toward the ical portion whose front edge terminatesback of the front Wall of the hopper and also a conical portion in frontof the fuel hopper to give the fuel and air leaving the burner acontracted or converging shape.

4:. A pulverized fuel burner comprising an outer pipe having between itsends a conical portion, a fuel hopper Whose front Wall is forward of thefront edge of said conical portion, an inner pipe inclosing a combustionair passage and affording between it and the outer pipe a passage forfuel and for fuel at'omizing and conveying air, part of the inner pipehack of the front edge of said conical portion of the outer pipeconverging rearwardly and affording a forwardly contracting passage forthe passage fuel inlet, and an inlet for air common to both pipes.

5. A pulverized fuel burner comprising an outer pipe, a fuel hopper, aninner pipe inclosing a combustion air passage and affording between itand the outer pipe a passage for fuel and for fuel atomizing andconveying air, and an inlet for air common to both pipes, the outer pipehaving a conical portion Whose front edge terminates back of the frontWall of the hopper, the opposite front end portions of both pipesconverging toward the common axis of said pipes.

In testimony of which invention, I have hereunto set my hand, atlPhiladelphia, on this 14th day of July, 1915.

LARS H. BERGMAN.

